docs: def generate_topology(self, vcpu_num, cores=1, threads=1):
          """
          Generate CPU <topology> XML child
  
          Args:
              vcpu_num(str): number of virtual CPUs
              cores(int): number of cores
              threads(int): number of threads
  
          Returns:
              lxml.etree.Element: topology XML element
          """
  
          return ET.Element(
              'topology',
              sockets=str(vcpu_num),
              cores=str(cores),
              threads=str(threads),
          )